The decorative effect of packaging can be greatly enhanced by the use of decorative foil in combination with the printed matter. The decorative foil provides a lustrous, elegant quality to the package.
Various techniques have been used to apply decorative foil to packaging. The most popular method is hot stamping, also known as dry printing. Typically, hot stamping involves the use of a roll leaf foil which includes a sheet of a polymeric carrier such as polyester, acetate or cellophane. A release coating such as a wax is applied to the carrier, a lacquer or varnish is overlayed for resistance, a metal is vacuum-deposited or a pigmented vehicle is roller painted onto the coated carrier, and an adhesive coating is applied to the metal or pigmented layer. The foil is placed against the object to be imprinted and a die is pressed against the foil to transfer portions of the metal or pigmented layer corresponding to the pattern on the die onto the object, either by pressure or heat and pressure. If an ink design is desired on the same object, it can be placed on the object either before or after the foil pattern. In either case, very careful registration is required to ensure proper alignment of the foil and ink patterns.
Another transfer method involves imprinting onto the object, the desired pattern in an adhesive, and then pressing an adhesive-free foil against the adhesive pattern to imprint the foil pattern. As with the first method, if an ink design is desired in addition to the foil design, careful registration is required to align the ink and foil images produced in separate operations.
A third method of applying a foil pattern involves applying a reverse pattern in ink to a temporary carrier then applying a different reverse pattern in clear adhesive, pressing an adhesive-free foil against the temporary carrier, overlaying an adhesive and impressing the resulting sandwich against the object to form the foil pattern. In this method, too, the adhesive and ink designs are applied separately and thus must be carefully registered onto the temporary carrier to accomplish proper assignment of the ink and foil images.
The prior art methods suffer from several disadvantages. Since foil and ink are impressed in separate steps, careful registration is required to align the patterns. Registration is especially difficult with cylindrical and other non-flat surfaces, such as bottles and tubes. Most methods require the use of dies which have a raised image corresponding to the desired pattern. The step of pressing a metal die against a delicate foil is very sensitive and can damage the metallic or pigmented transfer or the receiving material, thus detracting from the appearance of the final article.
What has been needed, but not shown by the prior art, is a simple and economical method of placing an ink and decorative foil onto an object, without the necessity of raised image dies which can harm the object. The method of this invention satisfies this need.